Question 1
How does growth as a characteristic of living organisms differ in plants and animals ?
Answer
In plants growth occurs at meristematic tissues only ;while in animals growth occurs all over the body.
Question 2
State the role of active transport in animal nutrition.
Answer
- Reabsorbtion of sugars and some salts in the kidney.
- Absorption of digested food from the alimentary canal into the blood stream.
- Excretion of waste products from body cells.
- Absorption of digested food from the alimentary canal into the blood stream.
- Excretion of waste products from body cells.
Question 3
Cyanide lowers the rate of active transport. Explain?
Answer
Cyanide is an enzyme inhibitor, it affects the rate of active transport.
Question 4
The figure below is a diagram of a vertical section of a mammalian tooth.
- Name the part labelled A and B
A
B - State two ways in which structure D is adapted to its functions.
- List two ways of preventing gingivitis.
Answer
-
A - Enamel
B - Gum - 1. Contains blood vessels which supplies food nutrients and oxygen and remove carbon IV oxide and nitrogenous waste products.
2. Contains nerve endings for sensitivity. - 1. Regular brushing of teeth
2. Proper exercise of the teeth by eating tough fibrous food; -Eating foods that are rich in vitamin C.
Question 5
The figure below shows % saturation of oxygen in blood in fish as water passes along the gill plate.
-
i. Name the type of blood flow shown in the gill plate.
ii. Explain the advantage of the type of flow named in a (i) above. - State two organs in humans which display the type of flow named in a (i) above.
- State two ways in which floating leaves of aquatic plants are adapted to gaseous exchange.
Answer
-
i. Counter current flow
ii. Creates a steep diffusion gradient; that enhances the rate of gaseous exchange across the gill filaments/ increases rate of gaseous exchange; through diffusion. - - Kidney
- Placenta - - Stomata found only on upper epidermis to allow efficient gaseous exchange.
- Presence of large air-spaces/aerechyma tissue to enable floating and storage of air.